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Record Details

Record 44 of 18547
The Sensitivity of African Easterly Waves to Eastern Tropical Atlantic Sea-Surface Temperatures
External Online Source: doi:10.1007/s00703-011-0145-9
Author and Affiliation:
Druyan, Leonard M.(Columbia Univ., Center for Climate Systems Research, New York, NY, United States)
Fulakeza, Matthew(Columbia Univ., New York, NY, United States)
Abstract: The results of two regional atmospheric model simulations are compared to assess the influence of the eastern tropical Atlantic sea-surface temperature maximum on local precipitation, transient easterly waves and the West African summer monsoon. Both model simulations were initialized with reanalysis 2 data (US National Center for Environmental Prediction and Department of Energy) on 15 May 2006 and extended through 6 October 2006, forced by synchronous reanalysis 2 lateral boundary conditions introduced four times daily. One simulation uses 2006 reanalysis 2 sea-surface temperatures, also updated four times daily, while the second simulation considers ocean forcing absent the sea-surface temperature maximum, achieved here by subtracting 3 K at every ocean grid point between 0 and 15 N during the entire simulation. The simulation with 2006 sea-surface temperature forcing produces a realistic distribution of June-September mean precipitation and realistic westward propagating swaths of maximum rainfall, based on validation against Tropical Rainfall Measuring Mission (TRMM) estimates. The simulation without the sea-surface temperature maximum produces only 57% of the control June-September total precipitation over the eastern tropical Atlantic and about 83% of the Sahel precipitation. The simulation with warmer ocean temperatures generates generally stronger circulation, which in turn enhances precipitation by increasing moisture convergence. Some local precipitation enhancement is also attributed to lower vertical thermal stability above the warm water. The study shows that the eastern tropical Atlantic sea-surface temperature maximum enhances the strength of transient easterly waves and broadens the spatial extent of associated precipitation. However, large-scale circulation and its interaction with the African continent, and not sea-surface temperatures, control the timing and trajectories of the waves.
Publication Date: Jun 10, 2011
Document ID:
20120010522
(Acquired Jul 09, 2012)
Subject Category: METEOROLOGY AND CLIMATOLOGY
Report/Patent Number: GSFC.JA.00351.2012
Document Type: Journal Article
Publication Information: Meteorology and Atmospheric Physics; Volume 113; No. 1-2; 39-53
Publisher Information: Springer-Verlag G.m.b.H. and Co. K.G., New York, NY, United States
Contract/Grant/Task Num: NNX07A193G; NSF AGS-0652518; NSF AGS-0652518
Financial Sponsor: NASA Goddard Inst. for Space Studies; New York, NY, United States
Organization Source: Columbia Univ.; New York, NY, United States
Description: 15p; In English; Original contains color and black and white illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: BOUNDARY CONDITIONS; RAIN; OCEAN TEMPERATURE; SEA SURFACE TEMPERATURE; THERMAL STABILITY; WIND (METEOROLOGY); COMPUTATIONAL GRIDS; MONSOONS; TROPICAL REGIONS; SENSITIVITY
Availability Source: Other Sources
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Last Modified: July 09, 2012
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